“The first step toward understanding the polar regions is to develop a sense of place about the Arctic and Antarctic that makes them as separate in our minds as Austria and Australia, New York and San Francisco, or the Himalaya and the Adirondacks.” –Photographer Galen Rowell

Even though they are both at the "ends of the earth," the Arctic and Antarctic differ in many ways. The Arctic is a vast ice covered ocean surrounded by land. The pack ice ranges in thickness from a few inches to over 6 feet, below which are two-mile deep basins of seawater just above the freezing point. The icy surface of the Arctic Ocean is thin enough to be traversed by icebreakers, especially in summer when the extent of the ice is at a minimum. Since the ice sheets are constantly shifting, there is no actual pole marking 90 degrees North.

In contrast, the Antarctic is a landmass surrounded by ocean. Glaciers up to 4,700 meters (15,420 feet) thick and covering 98-99% of the land rest on the Antarctic continent. Nearly 85% of the world’s permanent ice is locked in Antarctic glaciers. Unlike the North, the South Pole is a permanent site marked by a brass pole with an engraved plaque.

The vast belt of warm water between the Arctic and Antarctic has caused the creatures in each region to evolve independently. For example, polar bears are only found in the Arctic and penguins only in the Antarctic. There are many land mammal species in the north, as animals have been able to migrate across the landmasses surrounding the Arctic. Comparatively warmer summers allow a greater range of animals to survive. Some of the 40 species of Arctic land mammals are migratory, going south in the much colder winters. Antarctica, on the other hand, is separated from its neighboring landmasses by the Southern Ocean. The largest land animal is the midge, a mere 1mm long. The Southern Ocean is extremely productive, and is an important habitat for seabirds and marine mammals.

In this section, you will find out why the Antarctic is colder than the Arctic, why the sun never sets on an Arctic summer night, and how humans have impacted the polar regions.